Markets around the world are lower today after a run on bank deposits in Cyprus over the weekend. That followed a decision by euro-zone officials to tax depositors to help pay for a national bailout. There's concern that the new bank crisis could spread to Italy, Spain and beyond.

Longer-dated Spanish government bond yields fell and German debt sold off on Thursday with expectations high that the European Central Bank will detail plans to buy struggling eurozone countries' debt to curb the bloc's long-running debt crisis.

European policymakers are working on "last chance" options to bring Greece's debts down and keep it in the euro zone, with the ECB and national central banks looking at taking significant losses on the value of their bond holdings, officials said.

A day after winning EU approval for a huge bank bailout, Spain's government imposed further austerity on the country Wednesday as it unveiled sales tax hikes and spending cuts aimed at shaving $79.85 billion off the state budget over the next two and a half years.

Crisis-weary investors scoffed Monday at what had appeared to be a hopeful turn in the European debt crisis: a victory for pro-Europe parties in a Greek election. U.S. stocks were little changed, and borrowing costs for Spain surged to alarming levels.

Bankers, governments and investors are starting to prepare for Greece to stop using the euro as its currency, a move that could spread turmoil throughout the global financial system. The worst-case scenario envisions governments defaulting on their debts, a run on European banks and a worldwide credit crunch reminiscent of the financial crisis in the fall of 2008.

Sunday's elections in France and Greece were a firm vote against austerity, and that means the future of the eurozone is again in doubt. Here's why the bond markets care so much -- and why you should, too.